For example, there is known a vehicle lamp in which a light source unit is detachably provided in an outer lamp housing constituted by a lamp body and a cover, and a light emitting element such as a light emitting diode is used as a light source of the light source unit.
In such a light source unit, the light emitting element serving as the light source, a wiring pattern for supplying current to at least the light emitting element, and a substrate formed with the wiring pattern are provided, and the substrate is disposed in a socket housing (e.g., JP2014041738A).
In the light source unit disclosed in JP2014041738A, the substrate is bent to have a U shape and a portion of the substrate is inserted into an opening portion formed in the socket housing.
By the way, in the light source unit as described above, it is necessary to secure a stable light-emitting state of the light emitting element by increasing the heat-dissipation of heat generated at the time of emission of light from the light emitting element.
However, in the light source unit disclosed in Patent Document 1, a portion of the substrate is located at the inside of the socket housing, and hence, there is a possibility that the heat released from the substrate is retained at the inside of the socket housing. Consequently, there is a risk that a sufficient heat-dissipation cannot be secured.